1. Field of the Invention
This invention relates to an improved turret type yarn winding apparatus provided with a rotatable turret such as a turret disc or turret arm, whereon a pair of spindles are rotatably mounted for winding a continuously fed yarn on bobbins mounted on the respective spindles alternately.
2. Description of the Prior Art
In a conventional turret type yarn winding apparatus, for example, one disclosed in the specification of U.S. Pat. No. 4,033,519, a pair of spindles, on each of which a bobbin is mounted, are disposed on a turret at positions symmetrical with each other with respect to the rotation axis of the turret, and a yarn shifting guide and a guide for forming bunch winds are disposed on a winding device for winding a yarn on a bobbin mounted to the spindle located at a predetermined winding position while the yarn is being traversed by a traverse device. In this apparatus, the yarn-transfer from one bobbin to another is carried out in the following manner.
A full size yarn package formed on the bobbin mounted to the spindle located at the winding position is shifted to a stand-by position by turning the turret, while a fresh bobbin mounted on the other spindle located at the stand-by position is displaced to the winding position. A guide for forming bunch winds is projected along the axis of the spindle, and simultaneously, a yarn shifting guide standing by on the free end side of the spindle and on the upstream yarn feed side of the traverse device is moved toward the turret in parallel with the axis of the spindle. Thus, the yarn being fed is displaced from the traverse region of the traverse device toward the outside thereof and, consequently, the yarn is displaced toward a blade cut or groove formed outwardly of the winding-width of a fresh bobbin mounted on the spindle which has been transferred to the winding position by the above-mentioned rotation of the turret. Then, the feeding yarn is caught on the blade cut or groove, and the yarn is stretched between the caught portion and the full size yarn package, and is finally cut to stop supply of the yarn to the full size yarn package, and simultaneously, start winding of the yarn on the fresh bobbin. After passage of a predetermined period of time, the yarn shifting guide is returned to its original position. At this point, the yarn being fed is caught by a yarn guide of the traverse device, and then, the yarn is wound on the predetermined winding position of the bobbin to form a yarn package. The above-mentioned guide for forming bunch winds is disposed so that when the fed yarn is displaced outside the traverse range by the yarn shifting guide, the yarn is prevented from coming to a position outside the winding-width of the package.
In the conventional technique, the yarn-transfer from one bobbin to another at the time of exchange of bobbins is accomplished in the above-mentioned manner. This conventional technique, however, is defective in that the ratio of success in catching the yarn end on the blade cut or groove of a fresh bobbin is low. As a result of investigations conducted to clarify the cause of this defect, it was found that, since the running direction of the yarn having contact with the bobbin is not in agreement with the direction of the blade cut formed on the bobbin and both the directions intersect each other, even if the yarn is shifted to the position of the blade cut, it is difficult to engage and catch the shifted yarn on the blade cut. According to the conventional technique, the time for the yarn shifting operation by the yarn shifting guide is inevitably prolonged and, therefore, bunch winds are excessively formed on the yarn package. Accordingly, there is brought about another defect that, when packages are delivered, these accumlated yarns created by the above-mentioned excessive bunch winds must be removed.